Displaying 20 results from an estimated 1000 matches similar to: "Cox proportional hazards confidence intervals"
2012 Feb 20
1
Reporting Kaplan-Meier / Cox-Proportional Hazard Standard Error, km.coxph.plot, survfit.object
What is the best way to report the standard error when publishing
Kaplan-Meier plots? In my field (Vascular Surgery), practitioners
loosely refer to the "10% error" cutoff as the point at which to stop
drawing the KM curve. I am interpreting this as the *standard error
of the cumulative hazard*, although I'm having a difficult time
finding some guidelines about this (perhaps I am
2011 Dec 10
2
p-value for hazard ratio in Cox proportional hazards regression?
Hi,
I'm new to R and using it for Cox survival analysis. Thanks to this great forum I learned how to compute the HR with its confidence interval.
My question would be: Is there any way to get the p-value for a hazard ratio in addition to the confidence interval?
Thanks,
Thierry
--
Thierry Panje Visiting Student Researcher
Department of Psychology Stanford
2012 Jul 12
1
Cox proportional hazard model and coefficients
Hi,
Here is the summary-output of the Coxph-model I used (the output is based on
the best final model i.e. all significant explanatory variables and their
interactions are included):
coxph(formula = Y ~ LT + Food + Temp2 + LT:Food + LT:Temp2 +
Food:Temp2 + LT:Food:Temp2)
n= 555
coef exp(coef)
se(coef) z
2011 Apr 01
2
Cox Proportional Hazards model with a time-varying covariate
Hello Everyone,
I'm learning how to perform various statistical analyses in R. I'm checking my understanding by replicating examples from my SAS books. Below is an attempt to replicate a Cox Proportional Hazards model with a time-varying covariate. I think I'm doing this correctly but am not completely sure. I would appreciate it if someone could double-check my results. In case
2005 Dec 13
1
Problem with understanding output of Cox model
Hi all,
I am using a 'tricked' Cox Hazard regression model for discrete choice
habitat modelling.
However, I'm having a hard time understanding the meaning of the first
line the following part of the summary() output:
Rsquare= 0.307 (max possible= 0.475 )
Likelihood ratio test= 91.8 on 12 df, p=2.23e-14
Wald test = 26.3 on 12 df, p=0.00977
Score (logrank) test = 58.6 on 12 df,
2006 Jan 03
1
p-value of Logrank-Test
Hello!
I want to compare two Kaplan-Meier-Curves by using the Logrank-Test:
logrank(Surv(time[b], status[b]) ~ group[b])
This way I only get the value of the test-statistic, but not the p-value.
Does anybody know how I can get the p-value?
Thanks in advance!
Verena Hoffmann
2007 May 01
7
logrank test
how do l programme the logrank test. l am trying to compare 2 survival curves
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2006 Sep 20
1
Stats question - cox proportional hazards adjustments
Hi useRs,
Many studies of the link between red meat and colorectal cancer use
Cox proportional
hazards with (among other things) a gender covariate.
If it is true that men eat more red meat, drink more alcohol and smoke more than
women, and if it is also true that alcohol and tobacco are known risk
factors then why does
it make sense to "adjust" for gender? I would think that in this
2003 Feb 20
1
Variable selection in Cox proportional hazards model?
Hello,
I need to implement variable selection procedures (such as stepwise and
backward selection) in Cox proportional hazards model, but can't seem to
find an R or S-plus command for these procedures. I am aware that these
can be done in SAS.
I would appreciate help from anyone who knows how to implement these
procedures in Cox models using S-plus or (preferably) R.
Thanks!
Regards,
2009 Mar 26
1
Centring variables in Cox Proportional Hazards Model
Dear All,
I am contemplating centering the covariates in my Cox model to reduce
multicollinearity between the predictors and the interaction term and
to render a more meaningful interpretation of the regression
coefficient. Suppose I have two indicator variables, x1 and x2 which
represent age categories (x1 is patients less than 16 while x2 is for
patients older than 65). If I use the following
2005 Sep 29
1
cox proportional-hazards regress for interval censor data
Hi. I used coxph(surv(start,end,event)~~event,data) to deal with interval
censor data.
Does anyone know similar samples using
coxph(surv(start,end,event)~~event,data)?
If you knows, can you tell me? I'll really appreciate it.
Thank you very much
R learner.
2017 Dec 14
0
permutation test for Cox proportional hazards regression model
I would like to perform a permutation test for Cox proportional hazards
regression model. I only find it for t-test and other tests (e.g. comparing
two medians).
Is there a way that I can perform a Cox PH model in R or SAS for the
LR-test?
I am doing the following
B <- 1000; LRtestx <- rep(NA,B);
Srv <- Surv(Time, Event);
for(j in 1:B){ LRtestx[j] <-
2004 Sep 22
1
Cox proportional hazards model
Good afternoon,
I am currently trying to do some work on survival analysis.
- I hope to seek your advice re: 2 questions (1 general and 1 specific)
(1) I'm trying to do a stratified Cox analysis and subsequently
plot(survfit(object)). It seems to work for some strata, but not for
others.
I have tumor grade, which is a range of 1 - 4.
When I divide this range of 1:4 into 2 groups, it
2006 Nov 13
1
Creating data for logistic regression and Cox proportional hazards regression
I know that mvrnorm from MASS (generously provided by Profs. Venables
and Ripley) can be used to generate multivariable normal data that can
be used in a linear regression with certain desired characteristics
(e.g. a given mean for each variable as well as a given
variance-covariance pattern). Is there any similar facility that can be
used to generate data for (1) a logistic regression and (2) a
2007 Oct 09
1
Visualize cox proportional hazards
Hello all
I would like to visualize the hazard ratios of a cox proportional
hazards model. I have seen some good examples in the New England
Journal of Medicine:
http://content.nejm.org/cgi/content/short/353/26/2747/F3
http://content.nejm.org/cgi/content/short/350/26/2654/F2
(I hope these are open access, but I am not sure)
And something similar in the book 'R Graphics' by Paul
2007 Dec 04
2
weighted Cox proportional hazards regression
I'm getting unexpected results from the coxph function when using
weights from counter-matching. For example, the following code
produces a parameter estimate of -1.59 where I expect 0.63:
d2 = structure(list(x = c(1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,
1, 0, 0, 1, 0, 1, 0, 1, 0, 1), wt = c(5, 42, 40, 4, 43, 4, 42,
4, 44, 5, 38, 4, 39, 4, 4, 37, 40, 4, 44, 5, 45, 5, 44, 5), riskset =
2006 May 31
1
Nesting in Cox proportional hazards survivorship analysis
Hello,
My advisor and I have been working on some survivorship analyses in R and we are
hoping to get some feedback on a particular issue involving nesting.
We are interested in patterns of food discovery by ant species. Our observations consist of time to discovery by an ant for three different food types, each of two different sizes. These data were collected at 6 plots located in each of
2007 May 07
2
computing logrank statistic/test
hie how do you compute the logrank test using R
what commands do you use my data looks something like just an example
treatmentgrp strata censoringTime survivalTime censoring act.surv.time
[1,] 2 2 42.89005 1847.3358 1 42.89005
[2,] 1 1 74.40379 440.3467 1 74.40379
[3,] 2 2
2008 May 09
2
how to check linearity in Cox regression
Hi, I am just wondering if there is a test available for testing if a linear fit of an independent variable in a Cox regression is enough? Thanks for any suggestions.
John Zhang
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2015 Feb 04
2
Interpretación de coeficientes en un cox proportional hazards con variable strata
Buenas.
Abajo pongo la salida de un modelo de cox , dónde he estratificado por
una variable de país (Countryb) y por otra (Q6). Además hay interacción
entre la variable mobilityPDurG2 (es una variable 0,1, y 0 es la
categoría de referencia) país.
La categoría de referencia para país es "united kingdom".
Mi duda surge si quiero calcular el hazard ratio para los que tienen un
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